Thermoplastic, predominantly isotactic homo- and copolymers of 1-butene, commonly referred to as poly-1-butene or polybutylene (conventional polybutene-1) are known in the art. Elastomeric polymers including elastomeric polybutylene-1 are also known in the art. In certain applications, there has been an effort to replace conventional polybutylene-1 with elastomeric polybutylene-1. These applications include film sheets and packaging film where the elastic nature of the elastomeric polybutylene-1 is preferred.
Packaging films are required to have certain characteristics which are desirable for the particular application. For example, films which are used for wrapping food such as vegetables, meat or fish, are minimally required to have a good puncture resistance and a good elastic recovery, sometimes also referred to as memory. A good puncture resistance is particularly important when packaging meat with bones because of the greater likelihood of the bones puncturing the film. Good recovery properties are particularly important in packaging food. Usually, the food is sold in service or convenience stores, or in grocery stores where many customers touch the packages. These touchings deform the film, and without the ability to sufficiently recover, the packaged food looks unfresh and often cannot be sold anymore.